Nicotine evoked efferent transmitter release onto immature cochlear inner hair cells.

Olivocochlear neurons make temporary cholinergic synapses on inner hair cells of the rodent cochlea in the first 2 to 3 wk after birth. Repetitive stimulation of these efferent neurons causes facilitation of evoked release and increased spontaneous release that continues for seconds to minutes. Presynaptic nicotinic acetylcholine receptors (nAChRs) are known to modulate neurotransmitter release from brain neurons. The present study explores the hypothesis that presynaptic nAChRs help to increase spontaneous release from efferent terminals on cochlear hair cells. Direct application of nicotine (which does not activate the hair cells' α9α10-containing nAChRs) produces sustained efferent transmitter release, implicating presynaptic nAChRs in this response. The effect of nicotine was reduced by application of ryanodine that reduces release of calcium from intraterminal stores.NEW & NOTEWORTHY Sensory organs exhibit spontaneous activity before the onset of response to external stimuli. Such activity in the cochlea is subject to modulation by cholinergic efferent neurons that directly inhibit sensory hair cells (inner hair cells). Those efferent neurons are themselves subject to various modulatory mechanisms. One such mechanism is positive feedback by released acetylcholine onto presynaptic nicotinic acetylcholine receptors causing further release of acetylcholine.

Serum anti-Müllerian hormone levels are negatively related to Follicular Output RaTe (FORT) in normo-cycling women undergoing controlled ovarian hyperstimulation.

BACKGROUND: Since in rodents anti-Müllerian hormone (AMH) has been shown to inhibit antral follicle responsiveness to FSH, we aimed at verifying whether a relationship exists between serum AMH levels and antral follicle responsiveness to exogenous FSH in normo-cycling women. METHODS: Serum AMH, estradiol (E(2)) and FSH levels were prospectively measured on cycle day 3 in patients undergoing controlled ovarian hyperstimulation (COH) with a time-release GnRH agonist and standardized FSH doses. In 162 patients, follicles were counted after pituitary suppression and before FSH administration (baseline; small antral follicles; 3-8 mm), and on the day of hCG (dhCG; pre-ovulatory follicles; 16-22 mm). Antral follicle responsiveness to FSH was estimated by the Follicular Output RaTe (FORT), determined by the ratio pre-ovulatory follicle count on dhCG × 100/small antral follicle count at baseline. RESULTS: Serum AMH levels were positively correlated with the number of small antral follicles at baseline (r = 0.59; P < 0.0001) and pre-ovulatory follicles on dhCG (r = 0.17; P < 0.04). Overall, FORT was 47.5 ± 1.4% and failed to be influenced by the woman's age, BMI or basal E(2) and FSH level. Conversely, multiple regression analysis showed that FORT was negatively correlated with AMH levels (r = -0.30; P < 0.001), irrespective of duration of COH and total FSH dose. CONCLUSIONS: The percentage of follicles that effectively respond to FSH by reaching pre-ovulatory maturation is negatively and independently related to serum AMH levels. Although the mechanisms underlying this finding remain unclear, it is in keeping with the hypothesis that AMH inhibits follicle sensitivity to FSH.

Antennapedia homeobox peptide enhances growth and branching of embryonic chicken motoneurons in vitro.

Spinal motoneuron development is regulated by a variety of intrinsic and extrinsic factors. Among these, a possible role for homeoproteins is suggested by their expression in the motoneuron at relatively late stages. To investigate their possible involvement in motoneuron growth, we adapted a novel technique recently developed in this laboratory, based on the ability of the 60 amino acid-long homeobox of Antennapedia (pAntp) to translocate through the neuronal membrane and to accumulate in the nucleus (Joliot, A. H., C. Pernelle, H. Deagostini-Bazin, and A. Prochiantz. 1991. Proc. Natl. Acad. Sci. USA. 88:1864-1868; Joliot, A. H., A. Triller, M. Volovitch, C. Pernelle, and A. Prochiantz. 1991. New Biol. 3:1121-1134). Motoneurons from E5 chicken spinal cord were incubated with pAntp, purified by panning on SC1 antibody and plated on polyornithine/laminin substrata without further addition of pAntp. After 24 h, neurite outgrowth was already extensive in controls. In cultures of motoneurons that had been preincubated with 10(-7) M pAntp, neurite length was doubled; a similar effect was obtained using postnatal muscle extracts. Morphological analysis using a neurofilament marker specific for axons indicated that the homeobox peptide enhances primarily axonal elongation and branching. To test the hypothesis that the biological activity of pAntp involves its specific attachment to cognate homeobox binding sites present in the genome, we generated a mutant of pAntp called pAntp40P2, that was still able to translocate through the motoneuron membrane and to reach the nucleus, but had lost the specific DNA-binding properties of the wild-type peptide. Preincubation of pAntp40P2 with purified motoneurons failed to increase neurite outgrowth. This finding raises the possibility that motoneuron growth is controlled by homeobox proteins.

Antenatal depressed mood and child cognitive and physical growth at 18-months in South Africa: a cluster randomised controlled trial of home visiting by community health workers.

AIM: To examine the child outcomes at 18-months post-birth of a population cohort of women with antenatal depressed mood, half of whom were randomly chosen to receive perinatal home visits from community health workers during pregnancy. METHOD: Pregnant women in 24 neighbourhoods (98% participation) were randomised by neighbourhood to: (1) standard clinic care (SC; 12 neighbourhoods; n = 594) or (2) the Philani Intervention Program, a home visiting intervention plus standard care (12 neighbourhoods; n = 644). The physical and cognitive outcomes of children of mothers with antenatally depressed mood (Edinburg Perinatal Depression Scale >13) in the intervention condition were compared at 18-months post-birth to children of mothers without depressed mood in pregnancy in both conditions. RESULTS: More than a third of mothers had heightened levels of antenatal depressed mood (35%), similar across conditions. Antenatal depressed mood was significantly associated with being a mother living with HIV, using alcohol and food insecurity. At 18-months, the overall cognitive and motor scale scores on the Bayley Scales of Development were similar. However, 10.3% fewer children of mothers with antenatal depressed mood in the intervention condition had cognitive scores on the Bayley Scales that were less than 85 (i.e., s.d. = 2 lower than normal) compared with children of mothers with antenatal depressed mood in the SC condition. Intervention children of mothers with antenatal depressed mood were also significantly less likely to be undernourished (Weight-for-Age Z-scores < -2). CONCLUSION: Cognitive development and child growth among children born to mothers with antenatal depressed mood can be improved by mentor mother home visitors, probably resulting from better parenting and care received early in life.

Stimulation of human epidermal differentiation by delta-notch signalling at the boundaries of stem-cell clusters.

BACKGROUND: Human epidermis is renewed throughout life from stem cells in the basal layer of the epidermis. Signals from the surrounding keratinocytes influence the differentiation of the stem cells, but the nature of the signals is unknown. In many developing tissues, signalling mediated by the transmembrane protein Delta1 and its receptor Notch1 inhibits differentiation. Here, we investigated the role of Delta-Notch signalling in postnatal human epidermis. RESULTS: Notch1 expression was found in all living epidermal layers, but Delta1 expression was confined to the basal layer of the epidermis, with highest expression in those regions where stem cells reside. By overexpressing Delta1 or Delta(T), a truncated form of Delta1, in primary human keratinocytes and reconstituting epidermal sheets containing mixtures of Delta-overexpressing cells and wild-type cells, we found that cells expressing high levels of Delta1 or Delta(T) failed to respond to Delta signals from their neighbours. In contrast, wild-type keratinocytes that were in contact with neighbouring cells expressing Delta1 were stimulated to leave the stem-cell compartment and initiate terminal differentiation after a few rounds of division. Delta1 promoted keratinocyte cohesiveness, whereas Delta(T) did not. CONCLUSIONS: We propose that high Delta1 expression by epidermal stem cells has three effects: a protective effect on stem cells by blocking Notch signalling; enhanced cohesiveness of stem-cell clusters, which may discourage intermingling with neighbouring cells; and signalling to cells at the edges of the clusters to differentiate. Notch signalling in epidermal stem cells thus differs from other progenitor cell populations in promoting, rather than suppressing, differentiation.

Maintenance of neuroepithelial progenitor cells by Delta-Notch signalling in the embryonic chick retina.

BACKGROUND: Neurons of the vertebrate central nervous system (CNS) are generated sequentially over a prolonged period from dividing neuroepithelial progenitor cells. Some cells in the progenitor cell population continue to proliferate while others stop dividing and differentiate as neurons. The mechanism that maintains the balance between these two behaviours is not known, although previous work has implicated Delta-Notch signalling in the process. RESULTS: In normal development, the proliferative layer of the neuroepithelium includes both nascent neurons that transiently express Delta-1 (Dl1), and progenitor cells that do not. Using retrovirus-mediated gene misexpression in the embryonic chick retina, we show that where progenitor cells are exposed to Dl1 signalling, they are prevented from embarking on neuronal differentiation. A converse effect is seen in cells expressing a dominant-negative form of Dl1, Dl1(dn), which we show renders expressing cells deaf to inhibitory signals from their neighbours. In a multicellular patch of neuroepithelium expressing Dl1(dn), essentially all progenitors stop dividing and differentiate prematurely as neurons, which can be of diverse types. Thus, Delta-Notch signalling controls a cell's choice between remaining as a progenitor and differentiating as a neuron. CONCLUSIONS: Nascent retinal neurons, by expressing Dl1, deliver lateral inhibition to neighbouring progenitors; this signal is essential to prevent progenitors from entering the neuronal differentiation pathway. Lateral inhibition serves the key function of maintaining a balanced mixture of dividing progenitors and differentiating progeny. We propose that the same mechanism operates throughout the vertebrate CNS, enabling large numbers of neurons to be produced sequentially and adopt different characters in response to a variety of signals. A similar mechanism of lateral inhibition, mediated by Delta and Notch proteins, may regulate stem-cell function in other tissues.

Neurotrophic activity of a homeobox peptide.

Homeoproteins are well known for their role in defining the shape of organs during early development. The late expression of some homeogenes in the nervous system suggests that they might have other, additional functions, possibly in neurite growth and target recognition. The 60 amino acid-long peptide corresponding to the homeobox of Antennapedia (pAntp) translocates through the membrane of neurons in culture and reaches their nuclei. This process is followed by an enhanced morphological differentiation of the neurons. Internalization by neurons is four-fold that observed with fibroplasts. This difference is abolished upon treatment with Endo-N which specifically cleaves alpha,2-8 bonds in polysialic acid. To understand the mode of action of the peptide, we constructed three mutants modified in their capacity to specifically bind promoters and/or to translocate through the cell membrane. The biological properties of the mutants demonstrate that the neurotrophic action of pAntp requires its internalization and integrity of its specific DNA-binding capacity.

Results of cochlear implantation in two children with mutations in the OTOF gene.

OBJECTIVE: The purpose of the study is to present the results of cochlear implantation in case of deafness involving mutations in the OTOF gene. This form of deafness is characterized by the presence of transient evoked otoacoustic emissions (TEOAE). In cases of profound deafness with preserved TEOAE, two main etiologies should be considered: either an auditory neuropathy (a retrocochlear lesion) or an endocochlear lesion. It is essential to differentiate these two entities with regards to therapy and screening. PATIENTS: We report two children who presented with profound prelingual deafness, confirmed by the absence of detectable responses to auditory evoked potentials (AEP), associated with the presence of bilateral TEOAE. Genetic testing revealed mutations in OTOF, confirming DFNB9 deafness. Both patients have been successfully implanted (with a follow-up of 18 and 36 months, respectively). MAIN OUTCOME MEASURES: Clinical (oral production, closed and open-set words and sentences list, meaningful auditory integration scale), audiometric evaluation (TEOAE, AEP) before and after implantation, and neural response telemetry (NRT). RESULTS: Both patients present a good quality of clinical responses and electrophysiological tests after implantation, indicating satisfactory functioning of the auditory nerve. This confirms the endocochlear origin of DFNB9 and suggests that these mutations in OTOF lead to functional alteration of inner hair cells. CONCLUSION: In the absence of a context of neurological syndrome, the combination of absent AEP and positive TEOAE should lead to a genetic screening for mutations in OTOF, in order to undertake the appropriate management.

Auditory neuropathy or endocochlear hearing loss?

AIMS: The purpose of the study was to define boundaries between endocochlear hearing loss and auditory neuropathy in children with congenital profound hearing loss and positive otoacoustic emissions. PATIENT: A child presented with bilateral profound hearing loss, which was confirmed by the absence of evoked auditory potentials at 110 dB and with conserved otoacoustic emissions. The lack of any relevant medical history, a normal neurologic pediatric examination, and the improvement obtained with powerful hearing aids suggested an endocochlear cause. Genetic testing identified mutations in OTOF, responsible for the DFNB9 recessive form of hearing loss. RESULTS: In recent years, cases of children with hearing loss associated with positive otoacoustic emissions have been labeled as "auditory neuropathy." Classically, this form of hearing loss is refractory to the use of hearing aids and cochlear implants. Mutations in OTOF lead to inner hair cells dysfunction, whereas the outer hair cells are initially functionally preserved. As this form of endocochlear hearing loss can be detected at a molecular level, genetic testing can be proposed for cases of nonsyndromic auditory neuropathy, as those children could benefit from cochlear implantation. CONCLUSION: It is advisable to reserve the term "auditory neuropathy" for patients who present hearing loss and conserved otoacoustic emissions in the context of a neurologic syndrome or for children with suggestive perinatal history. In other cases, genetic testing for mutations in OTOF should be carried out.

Promoter-specific regulation of gene expression by an exogenously added homedomain that promotes neurite growth.

pAntp, a 60 amino acid long peptide corresponding to the homeodomain of the Drosophila Antennapedia protein, translocates through neuronal membranes when added exogenously to neurons in culture, where it accumulates in the nucleus and promotes neurite outgrowth. We proposed that the peptide, once internalized, may compete for homeoprotein DNA binding sites. To investigate this point, we have produced a permanent fibroblast cell line which carries a luciferase reporter gene under the control of a 93 bp genomic region of the HOXD9 promoter with binding sites for homeoproteins. Externally added pAntp specifically down-regulates the expression of the reporter gene, suggesting that the neurotrophic effects observed previously are mediated by direct binding of pAntp to homeoprotein target sites.

Sensory organ generation in the chicken inner ear: contributions of bone morphogenetic protein 4, serrate1, and lunatic fringe.

The chicken inner ear is a remarkably complex structure consisting of eight morphologically distinct sensory organs. Unraveling how these sensory organs are specified during development is key to understanding how such a complex structure is generated. Previously, we have shown that each sensory organ in the chicken inner ear arises independently in the rudimentary otocyst based on Bone morphogenetic protein 4 (Bmp4) expression. Here, we compare the expression of Bmp4 with two other putative sensory organ markers, Lunatic Fringe (L-fng) and chicken Serrate1 (Ser1), both of which are components of the Notch signaling pathway. L-fng and Ser1 expression domains were asymmetrically distributed in the otic cup. At this early stage, expression of L-fng is similar to Delta1 (Dl1), in an anteroventral domain apparently corresponding to the neurogenic region, while Ser1 is expressed at both the anterior and posterior poles. By the otocyst stage, the expression of both L-fng and Ser1 largely coincided in the medial region. All presumptive sensory organs, as identified by Bmp4 expression, arose within the broad L-fng- and Ser1-positive domain, indicating the existence of a sensory-competent region in the rudimentary otocyst. In addition, there is a qualitative difference in the levels of expression between L-fng and Ser1 such that L-fng expression was stronger in the ventral anterior, whereas Ser1 was stronger in the dorsal posterior region of this broad domain. This early difference in expression may presage the differences among sensory organs as they arise from this sensory competent zone.

Combined use of pleural adenosine deaminase with lymphocyte/neutrophil ratio. Increased specificity for the diagnosis of tuberculous pleuritis.

UNLABELLED: Increased pleural fluid adenosine deaminase (ADA) activity is classically associated with tuberculous pleuritis. However, increased activity can also occur in a number of other diseases and this may negatively affect the diagnostic utility of ADA measurements and decrease its specificity for the diagnosis of tuberculosis (TB). The presence of ADA in pleural fluids reflects the cellular immune response in the pleural cavity and in particularly, the activation of T lymphocytes. Different disease entities are typically associated with the presence of particular types of leukocytes. OBJECTIVE: To determine whether the combined use of ADA activity and differential cell counts would provide a more efficient means for diagnosing tuberculous pleurisy than the use of ADA levels alone. METHODS: Biochemistry, cytology, and microbiology studies were performed on 472 consecutive pleural fluids. ADA and differential cell counts were determined on all exudative effusions. RESULTS: ADA activity in tuberculous effusions was significantly higher than in any other diagnostic group (p < 0.005). At a level of 50 U/L, the sensitivity, specificity, positive predictive value (ppv), negative predictive value (npv), and efficiency for the identification of TB were calculated at 91%, 81%, 84%, 89%, and 86%, respectively. When the additional requirement of a lymphocyte neutrophil ratio of 0.75 or greater was included, the sensitivity, specificity, ppv, npv, and efficiency for the identification of TB were calculated at 88%, 95%, 95%, 88%, and 92%, respectively. CONCLUSION: ADA, especially when combined with differential cell counts and lymphocyte/neutrophil ratios, remains a useful test in the diagnosis tuberculous pleuritis.

Sequential half-body irradiation as salvage therapy in chemotherapy-resistant multiple myeloma.

Fifteen patients with a median age of 58 years, having multiple myeloma resistant to conventional combinations of cytotoxic drugs, received sequential half-body irradiation as salvage therapy. Response was obtained in 53% (n = 8: group 1); this was objective in 40% (n = 6), being defined as 50% or greater reduction in paraprotein, clearance of light chains from the urine, or an unequivocal decrease in tumor bulk on an adequate marrow trephine biopsy; a further 13% (n = 2) just failed to meet these criteria but nevertheless had excellent subjective response. Median survival was 24 months. No objective or subjective improvement occurred in 47% (n = 7: group 2); median transient survival was 4 months. Short-term toxicity was limited to transient nausea in 30% (n = 5) and protracted pancytopenia in about one-half of the patients (n = 7), who remain dependent on intermittent RBC transfusions. Morbidity is only moderate, and the response rate of 53% in refractory patients suggests that sequential half-body irradiation has a definite place in managing patients with end-stage disseminated myelomatosis.

Erythrocyte osmotic fragility, serum creatine kinase and its isoenzymes related to body weight in porcine malignant hyperthermia.

Erythrocyte osmotic fragility, serum creatine kinase (CK) and its isoenzymes (CK-MM, CK-MB and CK-BB) were determined in pigs susceptible (SMH) and resistant (RMH) to malignant hyperthermia at three different body weights (Group 1, 10 to 25 kg; Group 2, 26 to 55 kg; Group 3, 56 to 95 kg). The halothane challenge test was used for determining susceptibility to malignant hyperthermia (MH). Significantly (P less than 0.05) greater erythrocyte haemolysis at saline concentrations of 80 to 100 mM NaCl occurred only between SMH and RMH pigs for body weight group 2. The determination of blood enzyme activities revealed also a significant (P less than 0.001) increase for total CK, CK-MM and CK-BB in SMH and RMH pigs of body weight Group 2. Furthermore in SMH pigs, total CK, CK-MM and CK-MB activities were significantly (P less than 0.05) greater in the animals of body weight Group 2. It was concluded that, in SMH pigs, weighing between 26 and 55 kg, there is a relationship between erythrocyte osmotic fragility, plasma CK, CK isoenzyme activities and muscle development.

Prediction of the halothane (Hal) genotypes by means of linked marker loci (Phi, Po2, Pgd) in Quebec Landrace pigs.

Quebec Landrace pigs (n = 896) were halothane tested and blood samples were taken for the determination of Phi, Po2 and Pgd phenotypes. The incidence of the halothane positive pigs was 5.3%. The frequencies of the favorable alleles PhiA, Po2S and PdgA were respectively 29.2%, 39.6% and 64.4%. The highest linkage disequilibrium was found between Hal-Phi (0.0606) followed by Hal-Pgd (0.0428) and Hal-Po2 (-0.0308). Alleles PhiB, PgdB and Po2F were associated respectively with 97%, 81% and 74% of Haln haplotypes. It was concluded that a selection in order to increase the favorable marker loci PhiA and PgdA would reduce the Haln frequency in Quebec Landrace pigs.

[Comparative evaluation of the acceptability of a new estradiol gel TX11323(A) and a reference gel]. / Evaluation comparative de l'acceptabilité du nouveau gel d'estradiol TX11323(A) et d'un gel de référence.

This randomized, crossed, single-blind study compared the acceptability and drying time of the new estradiol gel TX11323(A) (Estréva Gel, Laboratoire Théramex) to that of a reference gel (CEstrodose, Laboratories Besins-Iscovesco), in two phases. In phase 1, 48 healthy menopausal female volunteers applied 1.5 mg estradiol of each form of estradiol gel on the outer side of the arm for 8 days, with a free period of 7 days between the two treatments. Acceptability, evaluated by self-questionnaire and drying time for the two treatments were noted at day 1 and day 8. The second phase applied only to 16 subjects who followed the same therapeutic protocol, except that this time application was made on the antero-external side of the thighs. Only the subjectively and objectively quantified drying-time was taken into account. A significant difference was found in favor of TX11323(A) gel in terms of the following items: consistency, ease of application and penetration, quantity of gel to apply, sensation of lasting stickness. We note that 68.8% subjects prefer TX11323(A) gel and 27.1% prefer the reference gel (p = 0.001). The timed drying-time for TX11323(A) gel is significantly reduced, 40 to 50% on average depending on the phase, compared to that of the reference gel. The subjective evaluation of the subjects confirms this shorter drying time.

[Fertility following myomectomy by laparotomy in women aged over 38]. / Fertilité après myomectomie par laparotomie pour les femmes de plus de 38 ans.

OBJECTIVES: Uterine fibroids is the most common benign pathology during reproductive age. Fibroids are implicated as a possible cause of infertility. The mechanism of infertility may depend on the size and the location of the fibroids and remain unclear. Myomectomy is performed in case of symptomatic patients who want to preserve their reproductive potential or in case of infertile patients. There are few data concerning fertility following abdominal myomectomy in patients over the age of 38. PATIENTS AND METHODS: Retrospective study of a case series. Assessment of reproductive outcome after abdominal myomectomy among patients older than 38 years. RESULTS: Abdominal myomectomy was performed on 34 patients aged over 38 during. Among these patients, 25 (74%) were contacted and 15 (60%) tried to obtain a pregnancy. Seven patients (46%) needed a new intervention. Five patients (33%) required intra-uterine insemination or in vitro fertilization and embryo transfer postoperatively. Three patients obtained a pregnancy and two (13%) had a delivery. All pregnancies were obtained spontaneously. None infertile or nulliparous woman before surgery became pregnant postoperatively. CONCLUSION: After 38 years old, nulliparity and infertility before abdominal myomectomy seem to be a factor of poor prognostic to become pregnant after surgery.

No emergence of Echinococcus multilocularis in foxes in Flanders and Brussels anno 2007-2008.

Echinococcus multilocularis is highly endemic in red foxes in southern Belgium (region of Wallonia), especially in the higher located forested areas. The north of Belgium, including the regions of Flanders and Brussels, is more urbanized and has been colonized entirely by red foxes since the 1980s. A temperospatial analysis of compiled epidemiological data from 1996 to 2003 predicted a northwest spread of the cestode from Wallonia and the Netherlands towards Flanders and Brussels (Prev. Vet. Med. 2006, 76, 137-150). In 2007-2008, none of 187 examined foxes from the north tested positive (<2.8%, α = 0.01), compared to 1.7% in 1996-1999. This suggests that the parasite is not emerging in the examined area and the endemic region has not significantly extended northwest during the last decade. The possible reasons are discussed in the article, including the relatively low altitude, milder climate or low abundance of suitable intermediate hosts. The low prevalence in foxes and the generally low infection rate in humans imply that the risk for public health in Flanders and Brussels is limited anno 2007-2008.